Introduction Repeated failed transfers of good quality embryos indicate impaired implantation. Failed implantation is also associated with pregnancy complications such as fetal growth restriction (FGR). The aim of this study was to investigate the hypothesis that women achieving pregnancy after two or more failed embryo transfers (ETs) of good quality embryos have increased incidence FGR compared to those conceiving after the first ET.

Materials and Methods The authors conducted a retrospective case-note review of women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection ( ICSI) at the St Mary's Hospital, Manchester, between January 2000 and June 2008. FGR was defined as an individualised birth weight centile ≤5. Statistical comparisons were made with Fishers exact test, using p<0.02 as statistical significance due to the use of multiple comparisons.

Results Case notes for 364 eligible patients were identified: 125 conceived after two or more failed embryo transfers (study group) and 239 after the first embryo transfer (control group). The demographic characteristics of the two groups were similar (p>0.05). After the exclusion of multiple pregnancies, X/125 babies in the study group were found to have FGR, compared to Y/239 in the study group (p=0.047, 95% CI 0.05 to 0.99).

Conclusions Women conceiving a singleton pregnancy on a third attempt at IVF or ICSI may be at increased risk of developing subsequent FGR, although this did not reach statistical significance by our own rigorous definition. This may imply a common underlying pathology for failed implantation and FGR and suggests these women may benefit from increased fetal surveillance.